While you were out celebrating the Memorial Day weekend, an ISO of the newly leaked Windows 10 build 10125 surfaced on the Internet. You might expect that such a small change in release numbers -- build 10122 appeared only last week, and it was official -- would indicate little new to see. In fact, there are some important (read: not cosmetic) changes that you should know about.

Since this wasn't an official build, we won't be updating the "Where Windows 10 stands right now" post, but if history is a reliable indicator -- the leaked builds so far have been very much in the mainstream -- you can expect the features to show up in an official build sooner or later.

Let's start with the cosmetic. Yes, there are new icons. Yes, they're better than -- or at least different from -- the old ones. Figure 1 offers a look at the new, spiffed-up File Explorer. The Recycle Bin also has a new icon. Be still my beating heart.

The new Start menu also includes small reminders if you have installed new apps (I never did figure out how Microsoft defines "new," but it works well enough). There's a New flag to the right of the All Apps entry on the left of the Start menu, and in Tablet Mode, the hamburger icon gets a big, blue New dot.

On the taskbar, File Explorer gets a right-click Jumplist. The Edge browser doesn't have one yet -- and hovering over the Edge icon doesn't bring up multiple thumbnails for the various tabs, as IE did in earlier versions of Windows.

In the brave new 10125 world, when you click on Start > All Apps, then click on one of the group heads (such as "A"), you get the letter grid shown in Figure 2. I think of it as a hideous alternative to Windows 7's simple and easily organized cascading menus, but that's just me.

Figure 2. New A-Z index for All Apps should leave you nostalgic for Win7.

In Tablet Mode (Start > Settings > System > Tablet Mode, or use the icon at the bottom of the Notification area), there's a new back arrow next to the Start icon. If you're trying to run Windows 10 Tablet Mode on any device without a dedicated Back button (which at this point is almost anything but a Windows Phone), that Back button is a lifesaver. It should also lessen the clamor to bring back the Windows 8 swipe-from-the-left behavior.

Windows Hello (Start > Settings > Accounts> Sign-in Options) doesn't work yet for most cameras, so I haven't been able to test it. (In fact, on two of my PCs I couldn't even get in to Sign-in Options.) Look for new Windows 10 devices to include compatible cameras.

Edge has made a giant leap in build numbers -- from build 13.10122 to 15.10125 -- and there seem to be a few significant, noticeable improvements. At the very least, it can now run YouTube videos full-screen.

For a list of behind-the-scenes stuff that involves media played on Edge, see Microsoft senior program manager Jerry Smith's post on the Microsoft Edge Dev Blog.

Albums still don't work (or, at best, they work at an extremely slow pace) in Photos. Windows Store doesn't have music. Plug in a USB device and there's no prompt to import pictures. There's no OneDrive Universal app -- and OneDrive baked into Windows 10, without smart files, may be damaging to your health.

Stay tuned for updates. We sacrifice our PCs so that you don't have to.